Study On The Alteration Of ?1-antichymotrypsin In Brains Of Prion-infected Rodents

?1-Antichymotrypsin(?1-ACT),an acute-phase inflammatory protein,is an integral component of the amyloid deposits in Alzheimer's disease(AD),but limitedly reported in prion disease.To address the alteration of ?1-ACT in prion disease,the ?1-ACT levels in the brains of scrapie agents 263K-,139A-and ME7-infected rodents were analyzed.The levels of ?1-ACT were remarkably increased in the brains of the three kinds of scrapie-infected rodents,displaying a time-dependent manner during prion infection.Immunohistochemistry assays revealed the increased ?1-ACT mainly accumulated in the regions of cortex,thalamus and cerebellum of scrapie-infected animals.Immunofluorescent assays illustrated ubiquitously localization of ?1-ACT with GFAP positive astrocytes,Ibal-positive microglia and NeuN-positive neurons.Moreover,double-stained immunofluorescent assays and immunohistochemistry assays using series of brain slices demonstrated close morphological colocalization of ?1-ACT signals with that of PrP and PrPSc in the brain tissues of 263K-infected hamster.However,co-immunoprecipitation does not identify any detectable molecular interaction between the endogenous ?1-ACT and PrP either in the brain homogenates of 263K-infected hamsters or in the lysates of prion-infected cultured cells.Our data indicate that brain al-ACT is abnormally upregulated in various rodent models of prion diseases.Direct molecular interaction between al-ACT and PrP seems not to be essential for the morphological colocalization of those two proteins in the brain tissues of prion infection.